Make the Smart Choice

Fibre Channel or iSCSI? Until recently, the difference between these two storage area networking technologies was a moot point. Despite being considered costly and complex, Fibre Channel was the only viable option because iSCSI was thought to be too immature and slow for large-scale deployments.

Now, as companies such as LeftHand Networks and QLogic unveil their next-generation iSCSI offerings for 10 Gigabit Ethernet, and companies such as Hewlett-Packard begin to offer low-cost and easy-to-use Fibre Channel starter kits, IT executives finally have a real decision to make.

“iSCSI was definitely overhyped between 1997 and 2005, but it’s finally being adopted today at all layers of the education industry,” says Greg Schulz, senior analyst at the StorageIO group consultancy.

Both iSCSI and Fibre Channel are gigabit-speed technologies that enable IT teams to consolidate their storage networks into data center operations. However, they do so in different ways. iSCSI uses the existing Ethernet infrastructure to send commands over IP, while Fibre Channel requires specialized hardware, including adapters and switches, to create point-to-point, shared-loop and switched topologies to transfer data.

iSCSI’s use of ubiquitous network infrastructure makes it an attractive option for K–12 enterprises that are often budget-constrained, Schulz says. However, if performance is a major consideration, then Fibre Channel, despite its price, wins hands down.

Picking iSCSI

Cost was important, but not the deciding factor, for Ben Hansen in the choice of LeftHand Networks’ iSCSI SAN featuring six 9-terabyte nodes. Hansen, assistant director for information technology at Bend–La Pine (Ore.) Schools, says the total cost of the system is about $2.69 per gigabyte with a long-term maintenance contract.

The SAN was part of an effort to find a world-class solution and consolidate Bend–La Pine’s 25 schools and five support sites. Hansen needed to create a central repository so that more than 16,000 students and 2,000 staff members could access their pickup and drop boxes, as well as store and retrieve projects and other data.

The scope of the SAN effort and the fact that Bend–La Pine Schools is still growing at a rapid rate demanded a flexible, dynamic and easily deployed and supported system. “We needed a solution that would scale easily and predictably without requiring specialized skills that we did not already have in-house,” Hansen says.

The LeftHand Networks’ nodes each have a controller built in so Hansen can automatically cluster a group of nodes into a larger logical storage solution. “If we need to add another 9TB, we add a node, turn it on and we’re done. We don’t have to worry about buying another controller or upgrading it. We also know exactly what our costs are going to be,” he says.

The 2-gigabit-per-second connections to each node using two aggregated 1Gbps links are fast enough to meet requirements. “iSCSI does not require a substantial investment to upgrade. All you have to do is upgrade your switch and network interface cards, and you’re at 10G,” Hansen says.

iSCSI offers another advantage over a Fibre Channel network: ease of disaster recovery and continuity of operations. Because using the Ethernet infrastructure allows iSCSI to be stretched further than Fibre, Hansen was able to distribute two nodes away from the four at his main site.

“If we have an incident at one building, we could get the snapshot off the other site. Also, iSCSI does RAID [redundant arrays of independent disks] over our network, which eliminates any single point of failure. We have redundancy across drives and nodes, so we could lose a node and not lose data,” he says.

Favoring Fibre

Cost is secondary to speed and performance for Bob Clabaugh, director of network and data center operations at the Northwest Regional Education Service District in Hillsboro, Ore.

NWRESD hosts a range of critical, transaction-heavy applications for more than 20 school districts, such as a student information system, Oracle and SQL databases, a library application and a financial program.

“We have service level agreements [SLAs] with our user base and they are not very forgiving. When we have downtime or performance-related problems, we get [criticized],” Clabaugh says. “With iSCSI, you should be able to hook enough 1Gbps connections together to match the speed of our 4Gbps Fibre Channel network, but in reality that’s not the case — especially if you’re doing applications such as databases.”

Clabaugh and a team of nine engineers skilled in Fibre Channel support the EMC CLARiiON CX and AX environments and monitor the SAN closely to ensure that myriad compliance mandates, such as the Health Insurance Portability and Accountability Act and the Family Educational Rights and Privacy Act, are being met. Fibre Channel helps with this effort by requiring IT teams to specify, or zone, which piece of equipment is allowed to plug into each port. “That’s peace of mind that not just anyone can plug a piece of equipment in and gain access to the network,” he says.

Clabaugh uses iSCSI in his testing environment, but finds the gigabit speeds cumbersome and slow. “I have not experientially or through vendors found that iSCSI is in any way superior to Fibre Channel. Until that happens, I’ll stick with Fibre Channel,” he says.

It’s a sentiment echoed by James Klein, director of information services at Saugus Union School District in Santa Clarita, Calif. Klein, who also is running Fibre Channel for his production traffic and iSCSI in his test environment, says that the complexity of Fibre Channel is often overstated, while iSCSI’s is understated.

“Sure, you can plug iSCSI into a switch and it works, but you want it to be a little more complex than that. You want to set up multiple pathways and redundant switches,” he says. “However, Fibre Channel doesn’t have to be as complex as most people make it. Our needs aren’t as great at the district level as they are in the corporate world, so we just set up a dual path and fail-over without getting caught up in clustering switches.”